Conflicting results have been reported in small non-homogenous groups of children with chronic renal failure in terms of casual blood pressure and ambulatory blood pressure monitoring (ABPM) parameters and left ventricular hypertrophy (LVH). The aim of our study was to assess the value of ABPM and hematological and biochemical parameters in predicting LVH in children on chronic peritoneal dialysis (CPD). Echocardiography and 24-h ABPM were performed in addition to routine biochemical and hematological evaluations in 47 children on CPD (26 male, 21 female; mean age 14.74 +/- 3.52 years). Mean daytime systolic blood pressure (SBP) and mean daytime diastolic blood pressure (DBP) values were found to be higher than the mean casual SBP and DBP (p = 0.001) values. Thirty-three (70.2%) children had LVH. The correlations between the left ventricular mass index and ABPM variables were good. Stepwise multiple regression analysis revealed daytime SBP load (beta = 0.652; p < 0.01) and hematocrit (beta = -0.282; p < 0.01) to be independent predictors of LVH. The sensitivity, specificity, positive predictive value, and negative predictive values for the combination of the SBP load >15% and hematocrit value <31% for predicting LVH were 95 [95% confidence interval (CI) 76-99], 78 (95%CI 45-94), 91 (95%CI 73-98), and 88% (95%CI 69-96%), respectively. We conclude that: (1) LVH is prevalent in children on CPD, and (2) a target hematocrit level >31% and daytime SBP load <15% may be preventive for the progression of LVH in the follow-up of children on CPD.